Objective 02: Approaches to Maintenance Flashcards
Total Productive Maintenance (TPM)
A comprehensive structured approach to ensure reliability and develop a standardized maintenance program that applies to all aspects of maintenance
When is TPM appropriate to be used?
When a company wants a structured and formal means of improving maintenance and reliability
When is TPM not an appropriate means of improving maintenance and reliability?
When there are specific known area that need improvement
What are some approaches to maintenance management that focus on risk management?
- Reliability Centered Maintenance
- Risk-Based Inspection
- Statistical Risk Assessment
What are 2 major categories of maintenance?
- Preventive
2. Corrective
Preventive Maintenance
The maintenance carried out at predetermined intervals or according to prescribed criteria and intended to reduce the probability of failure or the degradation of the functioning of an item
Corrective Maintenance
The maintenance carried out after fault recognition and intended to put an item into a state in which it can perform a required function
What are 3 types of Preventive Maintenance?
- Condition monitoring and inspection
- Functional testing or failure finding
- Interval-based repair or replacement
Emergency Maintenance
Corrective Maintenance that has to be done immediately
When is the most efficient time to perform maintenance?
Just before failure
How is it possible to perform efficient maintenance?
- There is a good way to monitor the equipment
2. There is convenient time to perform it
What are some examples of Condition Monitoring?
- Monitoring oil filter differential pressure and replacing the filter when a pre-determined pressure is reached
- Inspecting a pressure vessel for corrosion or erosion by visual inspection or by measuring wall thickness using ultrasonic inspection
- Performing oil analysis and replacing the oil when certain levels of contaminants are reached
- Doing vibration monitoring on rotating equipment, e.g. a pump, and replacing it when the vibration exceeds a certain value
- Using human senses to detect changes in sound, oil leakage, or other signs of deterioration
What does Functional Testing look for?
Hidden Failures
Hidden Failure
A failure that does not become evident when it occurs because the function is not required at that time, or is only activated intermittently
When is Functional Testing especially relevant?
For protective devices that are not needed very often
What are some examples of Functional Testing?
- Checking an overspeed switch to make sure it trips at the correct speed
- Verifying the correct operation of a pressure switch
- Starting a backup generator on a monthly basis to verify its operation
- Exercising shutoff valves to prevent them from seizing up
- Checking the spare tire on your car
Interval-Based Maintenance
Regular repair or replacement of components or equipment after a specified interval has passed - without regard for equipment condition or performance
What are some interval measures that could be used?
- (Calendar) time
- Running hours
- Number of operating cycles
- Number of starts
- Distance
When is Interval-Based Maintenance normally chosen?
- Condition-Monitoring is not cost-effective
- It is more convenient to do the repair/replacement in conjunction with another activity, e.g. yearly shutdown of the whole plant
What are some examples of Interval-Based Maintenance?
- Replacing an oil filter after 6000 km
- Overhauling a pump every 2 hours
- Replacing turbine blades after 100 000 running hours
- Repairing a starter after 500 starts
When does a failure call for Emergency Maintenance?
If it has a major impact on production or operation
When does a failure not call for Emergency Maintenance?
If it’s impact is small and backup equipment is available
Why don’t maintenance programs necessarily strive to prevent all failures?
It may prove more expensive to pay for expensive condition monitoring techniques or to replace equipment that is still in good condition rather than wait until the failure occurs, so long as the failure does not result in major safety hazers or large financial losses
